It's unlikely either of Planetsides will be open sourced for two reasons. 1) It's a security vulnerability since it would show how our authentication and login servers work. With PS2, it would also show people stuff they could exploit in the engine. 2) There's a lot of third party software that was licenced. We wouldn't have the rights to open source that stuff.

Makes sense, though that is full open source.

But what if you have written contracts and background checks on volunteer developers? Limiting who has access to it to say three - four people?

I have signed NDA's before.

It would also be possible to only disclose only partial code: what is needed for unit placement, coding and movement? Similar, world objects, if you provide parameters, code structure and a delivery format, new bases wouldn't have to be a huge issue.

Besides... several people already dug into the code and made modded items in it... Look up "Planetside terms of service violations" on YouTube. And secant was informing SOE over how hackers abused security breaches in the code. Even delivered ready made solutions to block cheaters.